The present invention relates to backlights for liquid crystal displays.
A typical liquid crystal display (LCD) has a liquid crystal display panel and a backlight arranged behind the display panel. The backlight includes a light guide plate, which is located behind the display panel, an edge light, which is arranged at one end of the backlight, and a light collector, which is arranged at the other end of the backlight. The light guide plate is typically made of an acrylic. A light emitting diode (LED) or an electroluminescence (EL) may be employed as the edge light. The light collector has a lens-like shape and transmits ambient light, such as sunlight or artificial light, to the light guide plate. Examples of backlights are described in "Recent Trends in Liquid Crystal Backlights, Monthly Display, June 1997: 75-85."
An LCD may be applied to the view finder of, for example, a video camera or a digital still camera. In such cases, outdoor usage may incur problems. When strong sunlight shines on the display panel from behind the user on a sunny day, the amount of light transmitted to the light guide plate decreases. This may lead to a decrease in the brightness of the display panel. In some cases, the decrease in brightness can make the images on the display panel barely visible.
Accordingly, it is an objective of the present invention to provide a liquid crystal display backlight that collects ambient light efficiently.